Upright vacuum cleaner with cyclonic airflow

ABSTRACT

A vacuum cleaner includes a first housing defining a cyclonic airflow chamber and a second housing defining a main suction opening that is in communication with an inlet of the cyclonic chamber. A suction source has a suction airstream inlet in communication with an outlet of the cyclonic chamber, and establishes a suction airstream that enters said main suction opening, passes through said cyclonic chamber, and passes to an outlet of said suction source. A substantial portion of particulates entrained in the suction airstream are separated therefrom when said suction airstream moves in a cyclonic fashion through the cyclonic chamber. A main filter assembly, preferably including filter medium comprising polytetrafluoroethylene (PTFE), is located in the cyclonic chamber so that a suction airstream moving from the main suction opening to the inlet of said suction source by way of the cyclonic airflow chamber passes through the filter medium thereof after said airstream moves in a cyclonic fashion within the cyclonic airflow chamber to remove residual particulates from the suction airstream before it leaves the cyclonic chamber. A HEPA filter can be provided to filter the suction airstream exhausted through the outlet of the suction source prior to the airstream being discharged from the vacuum.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to vacuum cleaners. Moreparticularly, the present invention relates to upright vacuum cleanersused for suctioning dirt and debris from carpets and floors.

[0002] Upright vacuum cleaners are ubiquitous. They are known to includean upper portion having a handle, by which an operator of the vacuumcleaner may grasp and maneuver the cleaner, and a lower cleaning nozzleportion which travels across a floor, carpet, or other surface beingcleaned. The upper portion is often formed as a rigid plastic housingwhich encloses a dirt and dust collecting filter bag, although the upperportion may simply be an elongated handle with the filter bag, and anexternal cloth bag, being hung therefrom. The cleaning nozzle ishingedly connected to the upper handle portion such that the upperportion is pivotable between a generally vertical upright storageposition and an inclined operative position. The underside of the nozzleincludes a suction opening formed therein which is in fluidcommunication with the filter bag.

[0003] A vacuum or suction source such as a motor and fan assembly isenclosed either within the nozzle portion or the upper portion of thecleaner. The vacuum source generates the suction required to pull dirtfrom the carpet or floor being vacuumed through the suction opening andinto the filter bag. A rotating brush assembly is typically provided inproximity with the suction opening to loosen dirt and debris from thesurface being vacuumed.

[0004] To avoid the need for vacuum filter bags, and the associatedexpense and inconvenience of replacing the bag, another type of uprightvacuum cleaner utilizes cyclonic airflow, rather than a filter bag, toseparate a majority of the dirt and other particulates from the suctionairstream. The air is then filtered to remove residual particulates,returned to the motor, and exhausted.

[0005] Such prior cyclonic airflow upright vacuum cleaners have not beenfound to be entirely effective and convenient to use. For example, withthese prior cyclonic airflow vacuum cleaners, the process of emptyingdust and dirt from the cyclonic chamber dirt collection container hasbeen found to be inconvenient, and often resulted in the spillage of thecup contents. Likewise, with these prior units, replacement of thefilter element has not been convenient. Other cyclonic airflow vacuumcleaners have been found to exhaust air which is not free of residualcontaminants. For example, one prior unit filters the airstream after itpasses through the cyclonic chamber, but thereafter passes the airstreamthrough the motor assembly where it is potentially recontaminated by themotor assembly, itself, prior to its being exhausted into theatmosphere.

[0006] Because the cyclonic action of such vacuum cleaners does notcompletely remove all dust, dirt, and other contaminants from thesuction airstream, it is necessary to include a filter downstream fromthe cyclonic chamber. As such, prior cyclonic airflow vacuum cleanershave heretofore included conventional, non-washable filter elementsincluding a conventional filtering medium to filter the airstream afterit passes through the cyclonic chamber. These prior filter elements havecaused considerable difficulties. A conventional filter that issufficiently fine to filter the airstream effectively unduly restrictsairflow and decreases the effectiveness of the cyclonic action. On theother hand, a coarse filter does not effectively filter the airstream ofresidual contaminants. Further, conventional filter media, such as paperor fibrous media, has been found to clog readily, thereby undulydecreasing airflow rates over time. Thus, a need has been found for acyclonic airflow vacuum cleaner with an effective filter positioned inthe cyclonic chamber for effectively filtering the airstream withoutclogging. Further, a need has been found for such a vacuum cleanerincluding a washable, re-usable filter element from which dirt is easilyextracted.

[0007] Accordingly, it has been deemed desirable to develop a new andimproved upright vacuum cleaner that would overcome the foregoingdifficulties and others while providing better and more advantageousoverall results.

SUMMARY OF THE INVENTION

[0008] In accordance with a first aspect of the present invention, anupright vacuum cleaner includes an upright housing and a nozzle basehingedly interconnected with the upright housing. The nozzle baseincludes a main suction opening in its underside. A cyclonic airflowchamber is defined in the upright housing and is adapted for separatingdust and dirt from a cyclonically circulating suction airstream. Themain suction opening is in fluid communication with the cyclonic airflowchamber. A suction source is located in the upright housing or nozzlebase and has a suction airflow inlet in fluid communication with thecyclonic chamber, and also includes a suction airflow outlet. A mainfilter assembly is located in the cyclonic chamber upstream from thesuction source for filtering dust and dirt from a suction airstream thatpasses through the cyclonic airflow chamber. The main filter elementextends upwardly within the cyclonic airflow chamber from a floor of adirt container portion of said housing that defines a lower portion ofthe cyclonic airflow chamber and that is adapted for receiving andretaining dirt and dust separated from the suction airstream. A conduitdepends into the cyclonic airflow chamber from an upper wall of thehousing, and the conduit is axially aligned and mates with an upper endof the main filter assembly whereby the main filter assembly and theconduit together define a hollow column structure in the cyclonicairflow chamber.

[0009] In accordance with another aspect of the present invention, avacuum cleaner comprises a first housing member defining a cyclonicairflow chamber adapted for separating entrained dirt and dust from acirculating airstream, and a second housing member defining a mainsuction opening. A first conduit fluidically connects the main suctionopening to an inlet of the cyclonic airflow chamber. A suction sourcehas a suction airstream inlet and a suction airstream outlet, and it isadapted for generating and maintaining a suction airstream flowing fromthe inlet downstream to the outlet. A second conduit fluidicallyconnects an outlet of the cyclonic airflow chamber to the suctionairstream inlet of the suction source. A main filter assembly includes afilter medium comprising a selectively permeable plastic material, andthe main filter assembly is located in the cyclonic chamber so that asuction airstream moving from the main suction opening to the inlet ofthe suction source by way of the cyclonic airflow chamber passes throughthe filter medium after the airstream moves in a cyclonic fashion withinthe cyclonic airflow chamber.

[0010] In accordance with still another aspect of the present invention,a vacuum cleaner apparatus includes a nozzle defining a main suctionopening, and a main suction source in communication with the mainsuction opening. The main suction source is adapted for establishing asuction airstream that moves into the main suction opening anddownstream into the suction source. A cyclonic chamber is placed incommunication with and between the main suction opening and the suctionsource, and the cyclonic chamber is adapted for imparting a cyclonicflow to the suction airstream whereby a portion of particulatesentrained in the suction airstream are separated therefrom, leavingresidual particulates entrained in the suction airstream. A filterassembly is located in the cyclonic chamber and includes a filtermembrane placed in covering relation with an outlet of the cyclonicchamber. Residual particulates entrained in the suction airstream areblocked from exiting the cyclonic chamber by the filter membrane, andthe filter assembly adapted for being selectively removed from thecyclonic chamber, washed to remove particulates from the membrane, andreplaced in the cyclonic chamber for further filtering operations.

[0011] In accordance with yet another aspect of the present invention, avacuum cleaner comprises a housing defining a cyclonic airflow chamberfor separating contaminants from a suction airstream. The housingfurther defines a suction airstream inlet and a suction airstream outletin fluid communication with the cyclonic airflow chamber. A nozzle baseincludes a main suction opening fluidically connected with the cyclonicairflow chamber inlet. An airstream suction source has an inletfluidically connected to the cyclonic airflow chamber outlet and asuction source exhaust outlet. The suction source selectivelyestablishes and maintains a suction airstream from the nozzle mainsuction opening to the suction source exhaust outlet. A main filterassembly is positioned in fluid communication between the cyclonicairflow chamber and the suction source and is adapted for filteringresidual contaminants from the suction airstream downstream relative tothe cyclonic airflow chamber. The main filter assembly comprising apolymeric filter membrane.

[0012] One advantage of the present invention is the provision of a newand improved vacuum cleaner.

[0013] Another advantage of the invention is found in the provision of avacuum cleaner with a cyclonic airflow chamber through which the suctionairstream flows for separating dust and dirt from the airstream and fordepositing the separated dust and dirt into an easily and convenientlyemptied dirt cup.

[0014] Still another advantage of the present invention resides in theprovision of a cyclonic airflow upright vacuum cleaner with a mainfilter that effectively filters residual contaminants from the suctionairstream between the cyclonic airflow chamber and the motor assemblywithout unduly restricting airflow and without premature clogging. Yetanother advantage of the invention is the provision of a cyclonicairflow upright vacuum cleaner with a final filter located downstreamfrom the suction motor assembly for filtering the suction airstreamimmediately prior to its exhaustion into the atmosphere.

[0015] A further advantage of the invention is the provision of a vacuumcleaner with a main filter, an auxiliary filter, and a final filterwherein the main, auxiliary, final filters are easily removable andreplaceable.

[0016] A still further advantage of the present invention is theprovision of a vacuum cleaner with a cyclonic airflow chamber and mainfilter element, wherein the main filter element is positioned in aremovable dirt cup partially defining the cyclonic airflow chamber forease of emptying the dirt cup and cleaning the filter.

[0017] A yet further advantage of the present invention resides in theprovision of a vacuum cleaner with a cyclonic airflow chamber and a mainfilter assembly situated in the cyclonic airflow chamber, wherein themain filter assembly includes a re-usable filter element that is easilyand repeatedly cleanable by washing.

[0018] Still other benefits and advantages of the invention will becomeapparent to those skilled in the art upon reading and understanding thefollowing detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The invention may take form in certain components and structures,preferred embodiments of which will be illustrated in the accompanyingdrawings wherein:

[0020]FIG. 1 is a perspective view illustrating a cyclonic airflowupright vacuum cleaner in accordance with the present invention;

[0021]FIG. 2 is a front elevational view of the vacuum cleanerillustrated in FIG. 1;

[0022]FIGS. 3 and 4 are left and right side elevational views,respectively, of the vacuum cleaner shown in FIG. 1;

[0023]FIG. 5 is a rear elevational view of the vacuum cleaner of FIG. 1;

[0024]FIG. 6 is a bottom plan view of the vacuum cleaner of FIG. 1;

[0025]FIG. 7 is a front elevational view of the upright housing portionof the vacuum cleaner of FIG. 1;

[0026]FIG. 8 is a perspective view of the final filter assembly inaccordance with the present invention;

[0027]FIG. 9 is a side elevational view in cross-section of a vacuumcleaner with cyclonic airflow in accordance with a preferred embodimentof the present invention showing suction airflow through the cyclonicairflow dust and dirt separating chamber;

[0028]FIG. 10 is an exploded perspective view of an upper housing memberand associated depending upper conduit of the vacuum cleaner of FIG. 9;

[0029]FIG. 11 is a cross-sectional view of the assembled upper housingmember and conduit of FIG. 10;

[0030]FIG. 12 is a perspective view of the upper conduit of FIG. 10;

[0031]FIG. 13 is an exploded perspective view of a dirt cup, main filterassembly, and filter mount means as employed in the vacuum cleaner ofFIG. 9;

[0032]FIG. 14 is a rear elevational view of the dirt cup, main filterassembly, and filter mount means of FIG. 13 in an assembled condition;

[0033]FIG. 15 is a rear elevational view of a preferred main filterassembly formed in accordance with the present invention; and, FIG. 16is a view taken along line A-A of FIG. 15.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Referring now to the FIGURES, wherein the showings are forpurposes of illustrating a preferred embodiment of the invention onlyand not for purposes of limiting the same, FIGS. 1-6 illustrate anupright vacuum cleaner A including an upright housing section B and anozzle base section C. The sections B,C are pivotally or hingedlyconnected through the use of trunnions or another suitable hingeassembly D so that the upright housing section B pivots between agenerally vertical storage position (as shown) and an inclined,operative position. Both the upright and nozzle sections B,C arepreferably made from conventional materials such as molded plastics andthe like. The upright section B includes a handle 20 extending upwardtherefrom by which an operator of the vacuum A is able to grasp andmaneuver the vacuum.

[0035] During vacuuming operations, the nozzle base C travels across thefloor, carpet, or other subjacent surface being cleaned. The underside24 (FIG. 6) of the nozzle base includes a main suction opening 26 formedtherein that extends substantially across the width of the nozzle base Cat the front end thereof. The main suction opening 26 is in fluidcommunication with the vacuum upright body section B through a passage30 and a connector hose assembly 34 (see also FIG. 5) or a like conduit.A rotating brush assembly 36 is positioned in the region of the nozzlemain suction opening 26 for contacting and scrubbing the surface beingvacuumed to loosen embedded dirt and dust. A plurality of wheels 38support the nozzle base on the surface being cleaned and facilitate itsmovement thereacross.

[0036] The upright vacuum cleaner A includes a vacuum or suction sourcefor generating the required suction airflow for cleaning operations.With reference particularly to FIGS. 5 and 9, a suitable suction source,such as an electric motor and fan assembly E, generates a suction forcein a suction inlet 40 and an exhaust force in an exhaust outlet 42. Theexhaust outlet 42 of the motor assembly is in fluid communication with adownstream final filter assembly F for filtering residual contaminantsfrom the airstream exhausted by the motor assembly immediately prior todischarge of the exhaust airstream into the atmosphere. The suctioninlet 40 of the motor assembly E is in fluid communication with anupstream elongated suction conduit 46 that extends upwardly from themotor/fan assembly E to an upper region of the upright section B whereit communicates with the cyclonic suction airflow dust and dirtseparating region G of the vacuum A to generate a suction force therein.

[0037] With reference now particularly to FIGS. 7 and 9, the cyclonicsuction airflow dust and dirt separating region G housed in the uprightsection B includes and is defined by an upper housing assembly 50 and amating dust and dirt cup or container 52. These sections 50,52 togetherdefine a generally cylindrical cyclonic airflow chamber 54. The upperhousing section 50 includes a suction airflow outlet passage 60 thatcommunicates with the cyclonic chamber 54 through an aperture 62. Theoutlet passage 60 also communicates with the motor/fan assembly E by wayof the elongated suction conduit 46. FIG. 9 shows that the elongatedsuction conduit 46 extends from the motor/fan assembly E upward tocommunicate with the upper housing suction outlet passage 60 so that thesuction inlet of the motor/fan assembly E is able to fluidicallycommunicate with the cyclonic chamber 54. It is preferred that theaperture 62 be centrally located in the cyclonic chamber 54.

[0038] The dirt cup or container 52 defining the lower portion of thecyclonic airflow dust and dirt separating chamber 54 is constructed forlarge capacity and ease of emptying the contents as necessary. The dirtcontainer 52 defines over half the total volume of the cyclonic chamber54. The capacity of the container 52 is maximized to lengthen theoperational time before the dirt container 52 must be emptied.Furthermore, the dirt container 52 is preferably at least partiallytransparent so that an operator of the vacuum is able to view the levelof dirt and dust L accumulated therein for purposes of determining whenthe container should be emptied.

[0039] The dirt container 52 is connected to the vacuum upright sectionB through use of a hinge assembly 90 that allows the dirt container 52to pivot (as indicated by the arrow P) between the illustrated closed,operative position and an open forwardly tilted position. Once the dirtcontainer 52 is pivoted into its open position, it may be pulled upwardand away from the section B and separated therefrom for ease of emptyingthe dirt container. A handle 96 is provided on the exterior of thecontainer 52 to facilitate operator movement of the container betweenthe open and closed positions, and a resiliently biased latch 98 retainsthe dirt container in the closed position for vacuuming operations.

[0040] The dirt container upper edge 100 defining an open upper end ofthe container 52 is preferably inclined downwardly in the direction awayfrom the handle 96 or front of the container 52. The upper housingsection 50 is formed with a complimentary mating inclined lower edge102, and a seal such as a gasket or other structure (not shown) ispreferably provided between the edges 100,102 to prevent air leakageinto the cyclonic airflow chamber 54. The inclined upper edge 100 of thedirt container 52 also ensures that, when the container is pivoted tothe open position, the upper edge 100 lies in a substantially horizontalplane. Therefore, the contents of the container are much less likely tospill when the container is opened during emptying operations.Preferably, the angle at which the upper edge 100 is inclined fromhorizontal is selected, in combination with the maximum distance thecontainer is able to be pivoted on the arc P when opened, such that whenthe container is fully opened, the upper edge lies in a substantiallyhorizontal plane.

[0041] The dirt cup 52 is shown in further detail in FIGS. 13 and 14. Itincludes a main filter support such as a post, stem, or like structure150 projecting upwardly from a floor or base 152. The floor 152 of thefilter support also defines the floor of the dirt cup 52 when the mainfilter support is seated and suitably secured in the dirt cup. When themain filter support is operatively positioned in the dirt cup 52, thepost 150 is centrally positioned in the cyclonic airflow chamber 54defined by the upper housing member 50 and the dirt cup 52 on a centralaxis 81.

[0042] A hollow, cylindrical main filter assembly K is positioned overthe main filter support 150. The filter assembly K is engaged in aninterference fit with vanes 154 and/or a disc-like plateau or boss 156located on the floor 152 of the filter support so that the filterassembly K is releasably, yet securely, retained in its operativeposition as shown herein, even when the dirt cup 52 is removed from thevacuum cleaner and inverted for purposes of emptying the contentsthereof. An upper filter ring 158, accommodating a gasket 159, isprovided along the uppermost edge of a main filter medium membrane 180,and the main filter assembly K extends upwardly from the floor 152 to alevel approximately equal to an upper edge 100 of the dirt cup 52. Mostpreferably, the uppermost edge of the main filter assembly K as definedby the ring 158 is also sloped in the same manner as is the dirt cupupper edge 100. Over the entire height of the dirt cup 52, an annularcyclonic airflow passage is defined between the main filter assembly Kand the surrounding portion of the dirt cup 52.

[0043] A preferred embodiment of the main filter assembly K isillustrated in further detail in FIGS. 15 and 16. The main filter mediummembrane 180 is defined in a hollow, tubular, cylindrical form from aplanar, pleated filter membrane. An upper end of the pleated membrane180 is seated in an annular groove 184 defined by the upper filter ring158. Likewise, a lower end of the pleated filter membrane 180 is seatedin an annular groove 186 defined by a lower filter ring 157. The rings157,158 are preferably defined from molded plastic, and the lower ring157 defines an aperture 188 that closely receives the boss 156projecting from the filter support floor 152 with a tight, friction fit.The upper filter ring 158 is conformed in a manner so that, when thedirt cup 52 is in its closed position, the gasket 159 mates in afluid-tight manner with the entire peripheral extent of the lowermostedge 166 of an upper conduit 160 (FIG. 9) depending into the cyclonicchamber 54 from the upper housing member 50 so as to prevent undesiredairflow through an axial space between the depending conduit 160 and thefilter assembly K. The pleated filter membrane 180 is internallysupported on an open frame structure 182 that extends axially betweenand interconnects the lower and upper filter rings 157,158. The openframe structure 182 does not impede airflow through the pleated filterelement 180, but ensures that the filter element will not collapse underthe force of the suction airstream J.

[0044] A preferred medium for the filter membrane 180 comprisespolytetrafluoroethylene (PTFE), a polymeric, plastic material commonlyreferred to by the registered trademark TEFLON®. The low coefficient offriction of a filter medium comprising PTFE facilitates cleaning of thefilter element by washing. Most preferably, the pleated filter medium180 is defined substantially or entirely from GORE-TEX®, a PTFE-basedmaterial commercially available from W. L. GORE & ASSOCIATES, Elkton,Md. 21921. The preferred GORE-TEX® filter medium, also sold under thetrademark CLEANSTREAM® by W. L. GORE & ASSOCIATES, is an expanded PTFEmembrane defined from billions of continuous, tiny fibrils. The filterblocks the passage of at least 99% of particles 0.3 μm in size orlarger. Although not visible in the drawings, the inwardly and/oroutwardly facing surface of the CLEANSTREAM® filter membrane 180 ispreferably coated with a mesh backing material of plastic or the likefor durability since it enhances the abrasion-resistance characteristicsof the plastic filter material. The mesh may also enhance the strengthof the plastic filter material somewhat.

[0045] Referring now also to FIGS. 10-12, the relationship of the upperhousing member 50 and the depending upper conduit 160 is described. Theconduit 160 projects centrally downwardly into the chamber 54 from a topwall 162 of the housing member 50. The upper conduit 160 is preferably ahollow cylindrical member with a passage 164 extending therethrough. Thepassage 164 is in fluid communication with the suction airstream outletpassage 60 through which the suction airflow J exits the cyclonicairflow chamber 54. The conduit 160 projects downwardly from the housingtop wall 162 so that the lowermost edge 166 thereof is approximatelyequal to the level of the lower edge 102 of the housing member 50. Also,the lower edge 166 is sloped in a manner that corresponds to the slopeof the housing member lower edge 102. The upper conduit 160 is connectedto the upper housing member 50 by any suitable means such as fastenersengaged in aligned bores 168 a,168 b (FIG. 10) respectively formed inthe housing member 50 and conduit 160. As mentioned, the gasket 159 isprovided along the joint between the lowermost edge 166 of the upperconduit 160 and the upper edge of the filter assembly K.

[0046] With reference now specifically to FIG. 12, an auxiliary filtersupport grid or framework 170 is provided and extends across the bore164, preferably in the region of the conduit lower edge 166. The openfilter support 170 provides a backing member for a foam, paper, orsimilar conventional auxiliary filter element 174 that removes anyresidual dust and dirt from the suction airstream J prior to its exitfrom the cyclonic airflow chamber 54 through the bore 164 and outletpassage 60. In case there is a break in the seal between the filterassembly K and the conduit 160, the auxiliary filter 174 will preventdirt or dust from being sucked into the motor/fan assembly E of thevacuum cleaner A. One or more tabs or teeth 176 project radiallyinwardly from the conduit 160 in the region of the framework 170 toengage the auxiliary filter element 174 so that the filter element issecured adjacent the framework 170 and will not be dislodged from itsoperative position by the force of gravity.

[0047] As is most readily apparent in FIG. 9, the main filter assembly Kand the upper conduit 160 together define a hollow cylindrical columnextending through the center of the cyclonic airflow chamber 54 entirelybetween the floor 152 and top wall 162. This preferred cylindricalcolumnar shape also results from the main filter assembly K and theupper conduit 160 having substantially the same outside diameter.

[0048] The suction airstream J established and maintained by themotor/fan assembly E enters an upper portion of the cyclonic dust anddirt separation chamber 54 through a generally tangential or offsetsuction airstream inlet 80 that is preferably horizontally oriented. Inthe preferred embodiment, as may be seen most clearly with reference toFIGS. 10 and 11, the cyclonic chamber airstream inlet 80 is formed inthe upper housing member 50, and it is noted that the inlet 80 isdisposed entirely on one side of a centerline 81 of the upper housingsection so as to induce a swirling flow in the chamber 54. As shown inFIG. 5, the suction airstream inlet 80 is in fluid communication with asuction airstream hose 82 through a fitting 84, and the airstream hose82 is, itself, fluidically connected with the main suction opening 26formed in the underside of the nozzle base C by way of the conduit 34and a fitting 86. As such, the main suction opening 26 is in fluidcommunication with the cyclonic chamber 54 through the passage 30, thehoses 34,82, and the cyclonic chamber suction inlet 80.

[0049] The vacuum A also comprises a final filter assembly F (see e.g.,FIGS. 1-3 and 5) adapted for filtering the suction airstream downstreamfrom the motor/fan assembly and immediately prior to its exhaustion intothe atmosphere. A preferred structure of the final filter assembly F isillustrated most clearly in FIG. 8 and comprises a suction airstreaminlet 120 which is connected downstream and in fluid communication withthe exhaust outlet 42 of the motor and fan assembly E. The inlet 120communicates with an elongated plenum 122 that opens to the atmosphereand houses a filter medium. A protective grid or grate structure issnap-fit or otherwise effectively secured over the plenum 122 to securethe filter medium in place. The filter medium is preferably a highefficiency particulate arrest (HEPA) filter element in a sheet or blockform. The filter medium is retained in position in the plenum by thegrid 124, but is easily replaced by removing the grid. As such, thoseskilled in the art will recognize that even if the motor/fan assemblycauses contaminants to be introduced into the suction airstreamdownstream from the main filter element H, the final filter assembly Fwill remove the same such that only contaminant-free air is dischargedinto the atmosphere.

[0050] Referring now primarily to FIGS. 5 and 9, the operation of thevacuum cleaning apparatus A is illustrated, with the flow of the suctionairstream indicated by use of arrows J. The motor/fan assembly E orother suction generator establishes a suction force at its suction inlet40, in the elongated suction conduit 46, and thus in the cyclonicseparation chamber 54. This suction force or negative pressure in thechamber 54 is communicated to the main suction opening 26 formed in thenozzle underside 24 through the hoses 82,34 and associated fittings.This, then, in combination with the scrubbing action of the rotatingbrush assembly 36 causes dust and dirt from the surface being cleaned tobe entrained in the suction airflow J and pulled into the upper portionof the chamber 54 through the generally tangential inlet 80.

[0051] As the suction airstream J enters the cyclonic chamber 54 throughthe inlet 80, it travels downwardly in a cyclonic fashion so that aportion of the dust and dirt entrained in the suction airstream areseparated therefrom and collected in the dirt cup 52 (as indicated atL). The suction airstream J then passes through the main filter assemblyK to remove residual contaminants therefrom, and moves upwardly throughthe main filter element K, through the auxiliary filter element 174, andinto the bore 164 of the depending conduit 160. The airstream J isprevented from bypassing the main filter element K by the gasket 159positioned axially between the filter assembly K and the conduit 160.The airstream J then exits the cyclonic airflow chamber 54 through theoutlet passage 60 and moves downwardly through the conduit 46 to theinlet 40 of the motor/fan assembly E and is then exhausted through themotor exhaust outlet 42 to the final filter assembly F where it isfiltered again by the HEPA filter to remove any contaminants that passedthrough the chamber 54, the main filter assembly K, the auxiliary filter174, and also any contaminants introduced into the airstream by themotor/fan assembly E, itself.

[0052] The position of the main filter assembly K, extending upwardlyfrom the floor 152, is highly desirable given that, as dust and dirt Lare collected, at least a portion M of the suction airstream passesthrough the accumulated dust and dirt L. The accumulation of dust anddirt L seems to act as yet another filter element which filters moredust and dirt from the airstream M. Also, the flow of the suctionairstream M downwardly through the accumulated dust and dirt L acts tocompact the dust and dirt L downwardly toward the floor 152 so that thecapacity of the dirt cup 52 is efficiently utilized to extend the timebefore the dirt cup must be emptied. As noted, a main advantage of thepresent invention is that the main filter assembly K can be cleaned bywashing it, either manually or in a dishwasher—since it isdishwasher-safe—to remove dust or dirt particles adhering to the filterelement.

[0053] The orientation of the inlet 80 will affect the direction ofcyclonic airflow, and the invention is not meant to be limited to aparticular direction, i.e, clockwise or counterclockwise. Those skilledin the art will certainly recognize that the term “cyclonic” as usedherein is not meant to be limited to a particular direction of airflowrotation. This cyclonic action separates a substantial portion of theentrained dust and dirt from the suction airstream and causes the dustand dirt to be deposited in the dirt cup or container.

[0054] The invention has been described with reference to the preferredembodiments. Obviously, modifications and alterations will occur toothers upon reading and understanding the preceding detaileddescription. It is intended that the invention be construed as includingall such modifications and alterations insofar as they come within thescope of the appended claims or the equivalents thereof.

Having thus described the preferred embodiments, the invention is nowclaimed to be:
 1. An upright vacuum cleaner comprising: an uprighthousing; a nozzle base hingedly interconnected with the upright housing,said nozzle base including a main suction opening in an undersidethereof; a cyclonic airflow chamber defined in said upright housing andadapted for separating dust and dirt from a cyclonically circulatingsuction airstream, said main suction opening being in fluidcommunication with said cyclonic airflow chamber; a suction sourcelocated in one of said upright housing and nozzle base and having asuction airflow inlet in fluid communication with said cyclonic chamberand a suction airflow outlet; a main filter assembly located in saidcyclonic chamber upstream from said suction source for filtering dustand dirt from a suction airstream that passes through said cyclonicairflow chamber, said main filter element extending upwardly within saidcyclonic airflow chamber from a floor of a dirt container portion ofsaid housing that defines a lower portion of said cyclonic airflowchamber and that is adapted for receiving and retaining dirt and dustseparated from said suction airstream; a conduit depending into saidcyclonic airflow chamber from an upper wall of said housing, saidconduit axially aligned and mating with an upper end of said main filterassembly whereby said main filter assembly and said conduit togetherdefine a hollow column structure in said cyclonic airflow chamber. 2.The upright vacuum cleaner as set forth in claim 1 further comprising: afinal filter assembly connected in fluid communication with said suctionairflow outlet of said suction source and adapted for filtering saidsuction airstream exhausted by said suction source prior to said suctionairstream being dispersed into the atmosphere, wherein said final filterassembly comprises a high efficiency particulate arrest (HEPA) filtermedium.
 3. The upright vacuum cleaner as set forth in claim 1 whereinsaid suction source is housed in said nozzle base and communicates withsaid cyclonic airflow chamber through said depending conduit, andwherein said main suction opening in said nozzle base communicates withsaid cyclonic airflow chamber through an airstream inlet located at anupper portion of said cyclonic airflow chamber, whereby, upon activationof said suction source, dust and dirt from a surface being cleaned areentrained in a suction airstream, said suction airstream traveling: (a)from said main suction opening in said nozzle base upwardly and intosaid cyclonic airflow chamber through said airstream inlet; (b)downwardly from said airstream inlet and in a cyclonic fashion withinsaid cyclonic airflow chamber so that said entrained dust and dirt areseparated from said suction airstream and deposited in said dirtcontainer; (c) through said main filter assembly and upwardly throughsaid depending conduit; and, (d) downwardly to said suction sourcehoused in said nozzle base.
 4. The upright vacuum cleaner as set forthin claim 3 wherein said main filter assembly includes a main filterelement that comprises an expanded polytetrafluoroethylene (PTFE)membrane.
 5. The upright vacuum cleaner as set forth in claim 4 whereinsaid filter medium of said main filter element blocks at least 99% ofparticles having a size of at least 0.3 μm.
 6. The upright vacuumcleaner as set forth in claim 1 wherein said dirt container, includingsaid filter assembly, is adapted for pivoting movement between an openposition, providing access to an interior region of said dirt container,and a closed position wherein said dirt container, together with anupper portion of said housing, defines said cyclonic airflow chamber. 7.The upright vacuum cleaner as set forth in claim 6 wherein said mainfilter assembly projects upwardly from said floor of said dirt containerto an upper end of said filter assembly located at a height thatcorresponds to a height of an upper edge of said dirt container, andwherein said depending conduit projects downwardly from said upperhousing wall to a lower edge located at a height that corresponds to aheight of a lower edge of said upper housing portion, said uprightvacuum cleaner further comprising: a gasket connected to one of saidlower edge of said depending conduit and upper end of said main filterassembly, said gasket effecting a fluid-tight seal between saiddepending conduit and said main filter assembly when said dirt containeris in its closed position.
 8. The upright vacuum cleaner as set forth inclaim 7 , wherein said lower edge of said upper housing member, saidupper edge of said dirt container, and said upper end of said mainfilter assembly are arranged parallel to each other and are eachinclined relative to a horizontal plane when said dirt container is inits closed position.
 9. The upright vacuum cleaner as set forth in claim1 wherein further comprising: an auxiliary filter element positioned insaid depending conduit and adapted to filter said suction airstreambefore said suction airstream passes to said suction source.
 10. Avacuum cleaner comprising: a first housing member defining a cyclonicairflow chamber adapted for separating entrained dirt and dust from acirculating airstream; a second housing member defining a main suctionopening; a first conduit for fluidically connecting said main suctionopening to an inlet of said cyclonic airflow chamber; a suction sourcehaving a suction airstream inlet and a suction airstream outlet andadapted for generating and maintaining a suction airstream flowing fromsaid inlet downstream to said outlet; a second conduit for fluidicallyconnecting an outlet of said cyclonic airflow chamber to said suctionairstream inlet of said suction source; and, a main filter assemblyincluding a filter medium comprising a selectively permeable plasticmaterial, said main filter assembly located in said cyclonic chamber sothat a suction airstream moving from said main suction opening to saidinlet of said suction source by way of said cyclonic airflow chamberpasses through said filter medium after said airstream moves in acyclonic fashion within said cyclonic airflow chamber.
 11. The vacuumcleaner as set forth in claim 10 wherein said main filter assembly iscylindrical in shape.
 12. The vacuum cleaner as set forth in claim 11wherein said filter medium of said main filter element comprises apleated planar material.
 13. The vacuum cleaner as set forth in claim 11wherein said filter medium of said main filter assembly is supported onan internal open framework cylindrical support structure.
 14. The vacuumcleaner as set forth in claim 11 wherein said main filter assembly isarranged coaxial with a central longitudinal axis of said cyclonicairflow chamber.
 15. The vacuum cleaner as set forth in claim 14 whereinsaid inlet of said cyclonic airflow chamber is horizontally oriented andarranged so that a suction airstream entering said cyclonic airflowchamber through said inlet of said cyclonic chamber moves cyclonicallyabout said main filter element.
 16. The vacuum cleaner as set forth inclaim 10 , wherein said filter medium of said main filter assemblyblocks passage of at least 99% of particulates that have a size of atleast 0.3 μm.
 17. The vacuum cleaner as set forth in claim 10 furthercomprising: an auxiliary filter located upstream relative to saidsuction airstream inlet of said suction source and downstream relativeto said main filter assembly, said auxiliary filter adapted forfiltering particulates from a suction airstream exiting said cyclonicairflow chamber prior to said residual contaminants entering saidsuction airstream inlet of said suction source.
 18. A vacuum cleanerapparatus comprising: a nozzle defining a main suction opening; a mainsuction source in communication with said main suction opening andadapted for establishing a suction airstream that moves into said mainsuction opening and downstream into said suction source; a cyclonicchamber placed in communication with and between said main suctionopening and said suction source, said cyclonic chamber adapted forimparting a cyclonic flow to said suction airstream whereby a portion ofparticulates entrained in said suction airstream are separated from saidsuction airstream leaving residual particulates entrained in saidsuction airstream; and, a filter assembly located in said cyclonicchamber, said filter assembly including a filter membrane placed incovering relation with an outlet of said cyclonic chamber whereby saidresidual particulates entrained in said suction airstream are blockedfrom exiting said cyclonic chamber, said filter assembly adapted forbeing selectively removed from said cyclonic chamber, washed to removeparticulates from said membrane, and replaced in said cyclonic chamberfor further filtering operations.
 19. The vacuum cleaner apparatus asset forth in claim 18 , wherein said filter membrane comprises apolytetrafluoroethylene (PTFE) material.
 20. The vacuum cleanerapparatus as set forth in claim 19 wherein said filter membrane blocksat least 99% of particles having a size of at least 0.3 μm.
 21. A vacuumcleaner comprising: a housing defining a cyclonic airflow chamber forseparating contaminants from a suction airstream, said housing furtherdefining a suction airstream inlet and a suction airstream outlet influid communication with said cyclonic airflow chamber; a nozzle baseincluding a main suction opening, said main suction opening beingfluidically connected with said cyclonic airflow chamber inlet; anairstream suction source having an inlet fluidically connected to saidcyclonic airflow chamber outlet and a suction source exhaust outlet,said suction source selectively establishing and maintaining a suctionairstream from said nozzle main suction opening to said suction sourceexhaust outlet; a main filter assembly positioned in fluid communicationbetween said cyclonic airflow chamber and said suction source forfiltering residual contaminants from said suction airstream downstreamrelative to said cyclonic airflow chamber, said main filter assemblycomprising a polymeric filter membrane.